void newt_PreviewMouseMove(object sender, MouseEventArgs e) {
var tabItem = e.Source as Wpf.Controls.TabItem;
if (tabItem == null)
tcMain.IsInTabDragDrop = false;
else if (Mouse.PrimaryDevice.LeftButton == MouseButtonState.Pressed)
DragDrop.DoDragDrop(tabItem, tabItem, DragDropEffects.All);
}
void newt_Drop(object sender, DragEventArgs e) {